Formbarkeitsverläufe

Formbarkeitsverläufe, often translated as "formability curves" or "ductility curves," are graphical representations used in materials science and engineering to illustrate the plastic deformation behavior of a material under tensile stress. These curves plot the true stress against the true strain, providing a detailed view of how a material behaves beyond its elastic limit.

The characteristic shape of a formbarkeitsverlauf reveals critical information about a material's ductility. Initially, the curve shows an increasing stress with increasing strain, representing the elastic and then the plastic deformation. A distinct peak on the curve indicates the ultimate tensile strength (UTS), the maximum stress the material can withstand before necking begins. After reaching the UTS, the engineering stress decreases as the material necks down, but the true stress continues to rise until fracture.

Formbarkeitsverläufe are essential for predicting a material's suitability for various manufacturing processes such as deep drawing, stamping, and bending. A material with a broad, high-reaching formbarkeitsverlauf generally exhibits good ductility and can undergo significant plastic deformation without fracturing. Conversely, a material with a narrow curve or one that fractures at low strains has limited formability. Analyzing these curves helps engineers select appropriate materials and optimize processing parameters to avoid defects like tearing or cracking.